1. Field of the invention
The present invention relates to an intermittent recording method and an intermittent recording apparatus for the intermittent recording of video signals by means of frame skipping.
2. Description of Related Art
In an intermittent recording apparatus, when recording video signals intermittently by means of time-lapse VTR for the purpose of surveillance, for example, video signals are recorded by dropping a picture at intervals, dropping one picture for every six pictures for example, in the unit of frame or field. This interval of dropping a picture is the intermittent recording interval. Generally in the prior art, appropriate recording time is set according to the recording capacity of the recording medium when recording, and the video signals are recorded intermittently at the intermittent recording intervals corresponding to the recording time.
FIG. 1 is a block circuit diagram illustrative of the constitution of a conventional intermittent, recording apparatus. In FIG. 1, numeral 1 denotes a recording time setting unit which selects a recording time mode from among a plurality of predetermined recording time modes, by means of a switch or the like. The recording time mode setting unit 1 sends the selected recording time mode to a system control unit. 2. The system control unit 2 controls the recording apparatus at the intermittent recording intervals preset beforehand according to the recording time mode which has been input. To sum up, the system control unit. 2 controls, an intermittent recording control unit 4 which controls the operations of a mechanism, a motor, or the like involved in the intermit, tent recording in accordance to a control signal from the system control unit, 2, and a video signal processing unit. 5 which processes the video signals to be recorded intermittently. Numeral 3 denotes a display unit having a liquid crystal display, for example, to display the recording time mode which is selected.
The operation will now be described below. FIG. 2 is a flow chart, illustrative of the procedure of determining the intermittent recording interval in the recording time mode setting unit. 1. In this example, such intermittent recording intervals are determined in advance that correspond to the recording modes from 2-hour mode to 480-hour mode. When a recording time mode which has been selected is input, the intermittent recording interval corresponding to the recording time mode is selected and output from the recording time mode setting unit 1 to the system control unit 2. In order to control the intermittent recording operation according to the intermittent recording interval which has been input, the system control unit 2 outputs control signal to the intermittent recording control unit 4 and the video signal processing unit 5, thereby intermittent recording is carried out. Information on the selected recording time mode is output to the display unit 3 to display the recording time mode which is selected.
The conventional intermittent recording apparatus the following problems because it is constituted as described above. Only the recording time modes prepared in the recording time mode setting unit 1 in advance can be selected. Because the intermittent recording interval is not displayed, the selected intermittent recording interval cannot be known unless the selected recording time mode is checked with the instruction manual. Moreover, when various types of recording media having different recording capacities are used, the user must select the recording time mode by calculating the recording time from the recording capacity of the recording medium which provides a reference of the recording time mode, thus causing an inconvenience of operation.